How often should gutters be cleaned?

Once a year covers most houses. Some need twice. It depends far less on the calendar than on what is growing above the gutter and how much of it lands in there.

Once a year is the normal answer

A house with no trees close by fills slowly. Grit off the tiles, a bit of windblown debris and whatever the birds bring settles into the run over twelve months, and an annual clearance keeps ahead of it. Miss one year and you will probably get away with it. Miss three and the job changes.

When to make it twice a year

• Trees close to the house, especially conifers, which drop all year rather than in one go.
• A north-facing run that stays damp and grows moss in the gutter itself.
• Moss coming off the roof. If the tiles are green, the gutter is where that moss ends up.
• A run that has already overflowed once. Whatever caused it is usually still upstream.
• A conservatory or lean-to underneath, where an overflowing gutter dumps straight onto the glass.

The best time to book

Autumn, once the leaves are actually down, is the most useful single visit of the year. Doing it in September while the tree is still full means doing it again in November. If you are on the twice-a-year pattern, late spring is the natural second visit, after the blossom and seed drop and before summer storms test the downpipes.

What happens when gutters are left for years

The debris does not stay loose. It breaks down into silt, holds water like a plant pot and sets hard, so it has to be dug out rather than flushed through. Grass and sycamore seedlings root in it. The weight pulls on the brackets and the run starts to dip. Meanwhile every heavy shower sends water down the same strip of wall, which is where the green streaks and stained render come from. Our guide to spotting a blocked gutter from the ground covers what to look for.

How to tell whether yours is due

Stand outside during heavy rain and watch the gutter line and the downpipes. Water sheeting over the front edge, joints dripping, or a downpipe that stays quiet while the gutter above it overflows all mean it is due now rather than next year.